Purpose: Perinephric and renal sinus fat invasion are classified as pT3a renal cell carcinoma (RCC) according to the 2002 American Joint Committee on Cancer. We investigated the prognostic significance of each of these pathological features using a cohort of pT3a patients.Materials and Methods: Between 1970 and 2002, 205 patients without direct adrenal invasion underwent nephrectomy for pT3a clear cell RCC.